Hot melt glue applicator



Jan. 2, 1968 R. c. TALBOT 3,361,112

HOT MELT GLUE APFLICATOR Filed Jan. 17, 1966 5 Sheets-Sheet 1 /Z IF J Y J INVENTOR.

ze/cmaeo [,1 121 4 507 I By W M a ATTORNEYS Jan. 2, 1968 R. c. TALBOT 33 L HOT MELT GLUE APPLICATOR Filed Jan. 17, 1966 5 Sheets-Sheet 2 INVENTOR. la /mew C 74L507' m &6 @WTTORNEYS R. C. TALBOT HOT MELT GLUE APPLICAIOR Jan. 2, 1968 '5 Sheets-$heet 3 Filed Jan. 17, 1966 INVENTOR. 90 44507- a United States Patent Ofifice 3,361,,1 l2 Patented Jan. 2, 1968 3,361,112 HOT MELT GLUE APPLICATOR Richard C. Talbot, Skokie, Ill., assignor to Peters Machinery Company, a corporation of Illinois Filed Jan. 17, 1966, Ser. No. 521,079 9 Claims. (Cl. 118-602) ABSTRACT OF THE DISLOSURE Glue applicator for hot melt glue in which a glue pot is provided which has an applicator roll rotatably mounted in the bottom of the pot out of contact with the glue in the pot and having a vertically extending applicator face moving out of and into the pot to apply glue to the vertical wall of a travelling carton. The glue in the glue pot is elevated to a glue trough mounted on an inside end wall of the pot adjacent and above the applicator roll. The drive shaft of the applicator roll has a spiral groove extending therealong having communication with the glue trough to meter glue to the applicator roll for application to the wall of a carton and the like. A parallel spirally grooved drive shaft has communication with the applicator roll and serves to remove surplus glue from the applicator roll and return the surplus glue to the glue trough.

This invention relates to improvements in glue applicators and more particularly relates to a hot melt glue applicator adapted to apply a quick setting glue to a succession of traveling articles, such as cartons and the like.

A principal object of the present invention is to provide a novel and improved form of applicator for applying a quick setting glue to certain parts of cartons and the like as the cartons pass by the applicator and so arranged as to maintain a uniform supply of glue in condition for application to the traveling articles for substantially instantaneous adhesion of the glued parts.

Another object of the invention is to provide a new and improved form of glue applicator particularly adapted to apply glue to a succession of traveling articles, arranged with a view toward applying hot melt glue to vertically extending portions of the articles and assuring a uniform supply of glue to the articles.

Still another object of the invention is to provide a glue applicator for applying hot melt glue to a succession of traveling articles, in which the glue is picked up from the bottom of the glue pot and is metered to a horizontal applicator roll rotatably driven and positioned to provide a glue applicator face on the outside of the glue pot, and in which surplus glue is returned to the glue pot by a vertically extending pump, to avoid the accumulation of glue about said glue applicator roll and the leakage of glue in the region of said glue applicator roll.

A still further object of the invention is to provide an improved form of glue pot for supplying and applying hot melt glue to a succession of traveling articles, in which a glue applicator roll is rotatably mounted at the bottom of the glue pot and extends outwardly therefrom and is supplied with glue from the top of the glue pot, in which parallel screw types of pumping means serve to meter glue to the glue applicator roll and to return excess glue therefrom, and in which the metering glue pumping means also forms a drive means for the glue applicator roll.

These and other objects of the invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawings wherem:

FIGURE 1 is a fragmentary top plan view of the front end portion of a glue pot constructed in accordance with the principles of the present invention, showing a glue applicator roll extending forwardly of the glue pot and also showing a vertical carton flap pressed into engagement with the glue roll and supplied with glue by the glue roll as it passes therealong;

FIGURE 2 is a vertical sectional view of the glue pot shown in FIGURE 1 taken substantially along the center of the glue pot;

FIGURE 3 is a transverse sectional view taken substantially along line III-III of FIGURE 2;

FIGURE 4 is a fragmentary sectional view taken substantially along line IV-IV of FIGURE 3 and showing the metering glue pump and its drive connection to the glue applicator roll;

FIGURE 5 is a fragmentary transverse sectional view taken substantially along line V-V of FIGURE 3 and showing the return pump, returning excess glue to the glue pot; and

FIGURE 6 is a fragmentary horizontal sectional view taken substantially along line VIVI of FIGURE 3, with certain parts broken away.

In the embodiment of the invention illustrated in the drawings, I have shown in FIGURES 1 and 2, a glue pot 10 for hot melt glue, which may be mounted on a carton closing machine or other apparatus in which articles are glued and adhesively secured together. As shown in FIG- URE 1 a vertically extending flap 11 of a carton is movable along the vertical face of a horizontal applicator roll 12, rotatably journalled in a front end wall 13 of the glue pot, as will hereinafter more clearly appear as this specification proceeds. A yieldable pressure finger 14 is diagrammatically shown as pressing the flap 11 into engage ment with the vertical applicator face of the glue applicator roll 12.

A succession of cartons may continually pass along the inside of the guide 14, and the flaps thereof may have glue applied thereto in a continuous operation, and then may be folded downwardly along a wall of the carton and pressed into engagement with the wall of the carton, to seal the carton closed. The quick setting qualities of the hot melt glue used assure a substantially instantaneously tightly closed carton, as the glued flap is pressed into engagement with the wall of the carton, by conventional pressure rollers or other pressure means.

The glue pot 10 is shown as being in the form of a thick walled cylinder 16, which may be made from a good heat conducting material such as brass or aluminum, or from any other material having good heat conducting qualities. The cylinder 16 is closed at its rear or inner end by an end closure plate 17 and is closed at its front end by the end closure 13, suitably secured thereto as by machine screws or a like securing means (not shown). An access opening (not shown) for the supply of glue, may open through the top of the cylindrical wall 16 and may be disposed adjacent the inner or rear wall 17 of the glue pot, and also may be closed by a suitable cover (not shown).

The inner end closure plate 17 and cylinder 16 are shown in FIGURE 2 as having a hole 18 extending therealong, which may be a drilled hole and which extends along the bottom portion of the cylindrical wall. The drilled hole 18 forms a mounting for a thermostat (not shown) controlling the energization of resistor heaters (not shown) extending within the wall of the cylinder 16 parallel to the drilled hole 18 on opposite sides of the thermostat as in an application Ser. No. 463,807 filed by me on June 14, 1965, and entitled Hot Melt Glue Applicator.

A thermometer 19 is shown as being mounted in a fitting 27, threaded within the wall 17 of the glue pot, and extending into the glue pot adjacent the bottom thereof. The thermometer 19 has a gauge head 21 on 2.9 the outer end thereof, indicating the temperature of glue within the pot. An arcuate shield 22 is suitably secured to the inside of the rear end closure 17 and extends axially inwardly therefrom over the top of the thermometer 19, to shield said thermometer and prevent inaccuracies in temperature readings, which may be caused by dropping cold glue on the thermometer.

A heat conducting bar 23 extends across the inside of the cylinder 16 and is suitably secured thereto at its opposite ends. A heat conducting bar 24 is spaced along the wall of the cylinder 16 toward the front end closure 13 of said cylinder, and extends across the cylinder in parallel relation with respect to the bar 23 and is suitably secured to said cylinder at its opposite ends. The bar 24 forms a support for an idler shaft 25 having a bearing 24? thereon, forming a bearing for a pick up gear 27 having wiping engagement with the side of a glue trough 29, picking glue up from the glue pot and trans ferring glue to the upwardly spaced glue trough 2?, as will hereinafter more clearly appear as this specification proceeds.

The glue supplied to the glue pot through the supply opening in the top of the pot may be of any commercial form of hot melt glue and may be in the form of flakes, pellets, sticks. In order to prevent unmelted glue freshly placed in the pot from getting to the pick up gear 27, I have separated the interior of the glue pot into a premelt section 31 and a glue transfer section 31, by a screen 32, having a periphery formed to conform to the inner periphery of the cylindrical wall 16, and forming a partition extending across said wall and abutting the iner side of the heat conductor bar 24 and suitably secured thereto.

The glue trough 29 has a depending flange 33 extending along the inside of the front wall 13 and suitably secured thereto as by machine screws 35. The glue trough includes an upright wiper arm 36 extendin" upwardly of a bottom wall 37, extending from the flange 33 towards the pick up gear 27. The bottom wall 37 extends from the wiper arm 36 along the inside of the wall 13 beneath a glue supply or inlet passageway and curves upwardly about said passageway to confine glue wiped from the pick up gear 27 by the glue trough and wiper arm 36, to flow through the glue supply passageway 39 extending within the end closure 13. The glue supply passageway 39 is shown in FIGURES l and 3 as inclined laterally with respect to the axis of rotation of the pick up gear and leading to a vertical cavity or drilled hole d-tl extending vertically along the end closure 13, coaxial with the axis of rotation of the glue applicator roll 12. The cavity 40 has a glue metering pump extending therealong in the form of a vertical shaft 41 having a single lead spiral groove 42 extending downwardly therealong and metering glue to the glue application roll 13, as the shaft 41 rotates. The shaft 4-1 forms a mounting and drive member for the glue applicator roll 12 and is journalled adjacent its lower end in a bearing 44- mounted in an enlarged diameter portion 45 of the cavity 4-0. The shaft 41 is journalled adjacent its upper end in a bearing 46, mounted in the upper end portion of the cavity 40, beneath a gear 47, secured to the upper end of said shaft, and abutting the top surface of the flange of the bearing :6, for rotatably driving said shaft and the applicator roll 12.

A passageway 49 leads inwardly or rearwardly of the cavity 40, at the bottom of the helical grooved portion of the shaft 41, and terminates into a perpendicular passageway 50', leading downwardly to a cavity for the glue applicator roll 12, and supplying glue to the inner end portion of said cavity. Rotation of the shaft 41 will thus effect the transfer of glue from the passageway 39 downwardly along the helical grooved portion 42 of said shaft to the horizontal passageway as and to the roll cavity 48 and face of the applicator roll 12 through the vertical passageway 5t A horizontal passageway 51 leads periphery of the applicator roll 12 adjacent the outgoing side thereof to a return cavity parallel to the cavity and having a return pump in the form of a shaft 55 extending along the return cavity 53. The shaft is rotatably mounted in said return cavity for raisglue from the bottom of the cavity 53 and returning glue to the glue pot through an axially extending passageway 56 opening to the interior of the cylinder 16 above the level of glue in said cylinder.

The shaft 55' has a helical groove 57 extending therealong and shown as having twice the lead of the helical grove 4-2 on the shaft 41, for conveying or pumping excess glue for return to the glue pot through the passageway 56.

The shaft 55 is journalled at its upper end portion beneath a coaxial drive gear 59 on a flanged bearing 61'), the flange of which forms a thrust bearing for said drive gear.

The end closure 13 has an upwardly opening recess 63 therein forming a recess for the gears 47 and 59 and for a drive gear 65 keyed or otherwise secured to a drive shaft 66, extending within the wall of the cylinder 16 and along said wall beyond the rear end thereof. The cavity 63 is closed by a top cover plate 67 having spaced hearing blocks 65" and 79 depending from the underside of said cover and secured to said cover as by machine screws. The bearing blocks 69 and 70 abut the tops of the shafts 31 and 55 and the gears 47 and 59 thereon to retain said shafts and gears from vertical movement with respect to said cavities.

The shaft 66 is journalled in the end wall 13 in a bearing '73 and extends along a drilled portion 74 of the wall of said cylinder, and is spaced radially inwardly therefrom. The end portion of the shaft 66 opposite from the bearing 73 is journalled in a bearing member 75 of brass or any other suitable bearing material. The bearing 75 extends into and through the end plate 17 from the outer end thereof into an enlarged diameter portion of the drilled passageway 74. The bearing member 75 abuts packing rings 76 in the enlarged diameter portion of the drilled passageway 74, and is suitably secured to the end plate 17 to retain said packing rings in position. A sprocket 77, secured to the rear end of the shaft 66, serves as a drive member for said shaft. The shaft 76 also serves as a drive member for the pick up gear 27 through a spur gear 79 pinned or otherwise secured to said shaft, in an opening 89, formed in the wall of the cylinder 16 and disposed adjacent the front end closure 13. The spur gear 7% meshes with the teeth of the pick up gear 27 to rotatably drive said pick up gear. A cover 81 closes the opening 30 in the wall of the cylinder 16. '1

The shaft 66 has a helical groove 83 extending therealong in the space between the gear 79 and the gear :65 within the bearing 73, to supply lubricant to said bearmg.

The gear 65 and the gears 47 and 59 may be a worm and worm gears or helical gears, for driving the two pumping shafts 41 and 55 in opposite directions to meter glue to the periphery of the applicator roll 12. and to return excess glue back to the glue pot 10. The geared drive connection is herein shown as being a worm and worm geared drive connection, for illustrative purposes only.

The recess 63 for the gears 4-7, 49 and 65 opens to the front of the front wall 13 and is closed by an end cover 35 having a block 86 extending inwardly therefrom engaging the forward end of the shaft 66 and the gear 65. The cover 85 and the block 86 may be made from a suitable bearing material, to act as an end thrust bearing for the helical gear 65 and the shaft 66.

The glue applicator roll 12 is shown in FIGURES l, 2, 3, 4 and 6 as being a stepped roll, having an upper re duced diameter vertical face and a lower larger diameter peripheral vertical applicator face 33, forming a glue car rying and applying surface, and engageable with a flap 11 radially from the of a carton, or with any other surface of an article to be glued, or applying hot melt glue to the surface of the flap as the flap is pressed into engagement with the applicator surface 88, by the leaf spring 14.

The amount of glue applied to the flap 11 or other article to be glued is controlled by a doctoring means having doctoring cooperation with the outgoing and incoming sides of the vertical applicator face 88 of the glue applicator roll 12. The doctoring means is shown in FIGURE 2 as comprising a pair of scraper bars 89 recessed within the forward end portion of the front wall 13 and adjustably secured thereto, for movement toward and from the outgoing and incoming sides of the applicator roll 12. Each scraper bar 89 has a stepped inner face 96 generally conforming to the form of the periphery of the stepped applicator roll 12, to maintain a predetermined thickness of glue on the applicator surface 88 of the glue applicator roll 12, to maintain a sufiicient quantity of glue on the face of the applicator roll 12 to glue the flap 11 or other article to be glued, to effect an efiicient seal between the flap and the surface to which it is adhesively secured. Each scraper 89 is recessed within a downwardly and forwardly opening recess 90 formed in the lower forward end portion of the end closure 13, and is adjustably secured there to as by machine screws 91 extending through slots 92 extending along each scraper bar for a portion of the length thereof. The machine screws 91, threaded in the front wall 13 afford a means for adjusting the spacing of the stepped faces of the scrapers 89 with respect to the periphery of the roll 12. A bottom plate 93 extends along the bottom of the front wall 13 and closes the bottom of the recess 90, cavity 48 and the cavities 4d and 53 and also forms a support for the bottom surfaces of the scraper bars 89. i

It may be seen from the foregoing that glue picked up from the pot 1d by the pick up gear 27 may be picked up from levels very close to the bottom of the pot, en abling operation of the applicator until the pot is substantially empty, and that the glue wiped into the trough 29 and metered to the periphery of the applicator roll 12 by the helically grooved rotatably driven shaft 4-1, maintains a continuous supply of hot glue to said applicator roll, any surplus glue being returned by the parallel helically grooved shaft 5'5 conveying or pumping the surplus glue upwardly and returning the surplus glue to the glue pot through the passageway 56. It should here be understood that during the entire gluing operation, the thick walled barrel-like glue pot is maintained sufficiently hot to keep the glue in a fluid state, so the glue scraped from the pick up gear 27 will readily flow to the shaft 4-1 and be metered to the glue applicator roll. The front end closure wall 13 is also sufficiently thick to retain the heat of the glue pot, and thereby keep the glue in a fluid state, to readily be returned to the pot by the rotating helically grooved pump shaft 55.

A continuous supply of glue to the vertical glue applying face of the applicator roll 12 may thus be maintained, a

and the glue so supplied is maintained in a sufficient fluid state by the heat of the glue pot to readily be applied to the article to be glued, the surplus glue being continually returned to avoid an undue accumulation of glue and leakage of glue around the glue applicator roll 12.

While I have herein shown and described one form in which the invention may be embodied, it may readily be understood that various variations and modifications in the invention may be attained without departing from the spirit and scope of the novel concepts thereof.

I claim as my invention: 1. A glue applicator particularly adapted to apply hot melt glue to a succession of traveling articles, comprising: a glue pot having a cylindrical wall struck about a horizontal axis and having front and back end closure walls, a glue trough within said glue pot and mounted on said front end closure wall above the bottom thereof,

a pick up gear having wiping engagement with the inner side of said glue trough and mounted for rotation from a position close to the bottom of said glue pot to a position adjacent the top thereof,

a shaft extending along said glue pot parallel to the axis of rotation of said pick up gear and adjacent the top of said glue pot,

a pinion on said shaft rotatably driving said pick up gear,

a glue applicator roll rotatably mounted in said front end closure wall adjacent the bottom thereof for rotation about a vertical axis and extending outwardly of the outer end of said front end Wall,

a vertical cavity in said front end wall extending vertically therealong coaxial with the axis of rotation of said glue applicator roll,

a glue metering pump rotatably mounted in said cavity and forming a drive member for said glue applicator roll,

an inlet passageway leading from said glue trough along said front end closure wall to said glue pump,

a second vertical cavity parallel to said first cavity,

a passageway from said glue applicator roll to said second cavity,

a passageway from said second cavity to said glue pot adjacent the upper end portion of said cavity,

a glue return pump in said second cavity, returning surplus glue to said glue pot,

means driven from said shaft for driving said glue metering and return pumps in opposite directions,

and doctor means regulating the amount of glue carried by said glue roller for application to a traveling article.

2. The structure of claim 1,

wherein the glue pumps comprise individual oppositely rotating vertical shafts journalled in said cavities and having helical grooves extending therealong.

3. The structure of claim 2,

wherein the helical grooves extending along said glue metering pump to said glue applicator roll are single lead grooves,

and wherein the helical grooves returning glue to said glue pot are double lead helical grooves.

l. The structure of claim ll,

wherein the doctoring means comprise scraper blades recessed within said front wall along the bottom thereof and having scraping end portions generally conforming to the periphery of said glue applicator roll.

5. The structure of claim 2,

wherein heating means extend within and along the cylindrical wall of said glue pot and serve to melt and maintain the glue therein in a fluid condition,

wherein screen means separate said pick up gear from said glue supply opening,

and wherein the doctoring means comprise scraper blades recessed within said front end closure wall at the bottom thereof and having doctoring end portions generally conforming to the periphery of said glue applicator roll at the outgoing and incoming sides of the applicator face thereof, and mounted in said front end closure wall for adjustable movement with respect to the periphery of said glue applicator roll.

d. A glue applicator particularly adapted to apply hot melt glue to vertical faces of a succession of continuously travelling articles, comprising:

a thick walled glue pot having parallel end walls,

a glue trough within said glue pot,

means mounting said glue trough to the inside of an end wall of said glue pot above the bottom of said glue pot,

power driven means transferring glue from said glue pot to said glue trough,

a glue applicator roll mounted at the bottom of said glue pot for rotation about a vertical axis and having a vertical applicator face movable into and out of said end Wall of said glue pot, pumping means having an intake having communication with said glue trough and an outlet having communication with said glue applicator roll for metering glue from said glue trough to the downwardly spaced applicator face of said glue applicator roll,

other pumping means having communication with said applicator roll at one end and with said glue trough at its opposite end for removing surplus glue from said applicator roll and elevating surplus glue to said glue pot.

7. A glue applicator in accordance with claim 6, Where in the pumping means metering glue to the applicator face of said glue applicator roll comprises a vertical shaft forming a support and drive shaft for said glue applicator roll and having an outwardly opening helical glue I1.il ing groove leading downwardly therealong, to lower glue from said glue trough for application to said glue applicator roll, and wherein the pumping means returning surplus glue to said glue trough comprises a parallel vertical shaft having a helical outwardly opening glue conveying groove leading upwardly therealong, and driven in an opposite direction from the direction of rotation of said first shaft for elevating surplus glue from said glue applicator roll to said glue trough.

glue applicator roll, and wherein other passageway means aJe provided from the periphery of said glue ap plicator roll to said second mentioned vertical shaft.

9. A glue applicator in accordance With claim ll, Wherein a horizontal shaft extending along the top of said glue pot between said vertical shafts drives said power driven means applying glue to said glue trough, and wherein a geared drive connection is provided from said horizontal shaft to said parallel pumping shafts, for rotatably driving said pumping shafts in opposite directions to meter glue to said glue applicator roll and to return surplus glue to said glue pot.

References Cited R. 1. SMITH, Assistant Examiner. 

